Steel alloy



Patented Dec. 8, 1931 v UNITED STATES PATENT OFFICE ADOLF FRY, OF ESSEN, GERMANY, ASSIGNOR, BY MESNE ASSIGNMENTS, TO THE NITRALLOY CORPORATION, A CORPORATION OF DELAWARE STEEL ALLOY N Drawing. Application filed May 6!, 1927,

alloys are easily produced, acquire great hardness in their marginal layers With relatively high hardness penetration when subjected to nitrogenization, and are distinguished further by particularly good prop erties of strength (in particular toughness and insensitiveness towards temper brittleness) and by their being well suited for heat treatment in large cross sections. This object is'attained according to the invention by using for the manufacture of the above-mentioned articles steel alloys which contain, either separately or in any desired combination, 1 to 8 per cent of silicon, manganese, nickel, chromium, molybdenum, tungsten, vanadium, titanium or zirconium, less than (1.5 per cent of aluminium, and up to 0.7 per centof carbon.-

The following are representative examples 5 of alloy steels falling within the range above indicated and showing when nitrogenized the characterizing properties of surface hardness, hardness penetration, toughness and insensitiveness toward temper brittleness above mentioned:

Example 0 Al Cr -Mn Mo Si If the total percentage of silicon, manganese, nickel, chromlum, molybdenum, tungsten,vanad1um,t1tan1um or zlrconium, elther separately or in any desired combination,

loys which has not yet been disclosed, which Serial No. 189,457, and in Germany June 2, 1926. Renewed October 29, 1930.

amounts to between 4 to 8 per cent, preferably such steel alloys may also be employed for the manufacture of the articles mentioned, which contain 0.5 to 2 per cent of aluminium. In this case it is proper to increase the percentage of aluminium, Within the limits stated, in accordance with the total percentage of the other alloy constituents.

The subject matter of the next preceding paragraph forms the basis of my divisional application Serial No. 557,366 filed August 15, 1931.

WVhat I claim and desire to secure by Letters Patent, i's:

1. An article hardened in its marginal layers by nitrogenization consisting of an alloy containing up to 0.7% of carbon, 1 to 8% of chromium, less than 0.5% of aluminium, and the principal portion of the remainder 1ron.

2. An article hardened in its marginal layers by nitrogenization comprising an alloy containing up to 0.7% of carbon, 1 to 8% of at least one of the elements of the group, silicon, manganese, nickel, chromium, molybdenum, tungsten, vanadium, titanium and zirconium, less than 0.5% of aluminium, and the principal portion of the remainder being 1ron.

The foregoing specification signed at Cologne, Germany, this 16th day of April,

ADOLF FRY. 

